Filling thread tensioning means

ABSTRACT

A flat weaving machine is operable to form a shed terminating at a fell of a cloth, to enter a filling thread into said shed along a predetermined line, to cut off said filling thread, and to beat up said filling thread against said fell. The machine comprises an intermittently rotatable reed roller consisting of a reed shaft and a multiplicity of discs co-rotationally mounted on said reed shaft and formed with thread-engaging edge portions which are adapted thus to beat up successive filling threads against said fell as said reed roller is intermittently rotated in a predetermined direction. Tensioning means are provided for maintaining the tension of said filling thread as it is beaten up and comprise two stationary spring tongues, which are disposed at opposite ends of said reed roller and bear on the outer end faces of those said discs which are disposed at said opposite ends of said reed roller. Said tongues are adapted to clamp opposite end portions of said filling thread against said outer end faces when said filling thread has been cut off. Said tensioning means also comprise two thread tensioners disposed adjacent to opposite ends of said reed roller and comprising backing means disposed adjacent to said predetermined line. Said tensioners are pneumatically operable to force said filling thread against said backing means when, and only when, said filling thread has thus been entered into said shed.

United States Patent [191 Filter et al.

[ Nov. 5, 1974 i 1 l llrLlNG 'lHREAl) 'llCNSlONlNG MEANS [75] inventors: Walther Filter, Langenhagen; Claus Filter, Rethem/Aller, both of Germany [73] Assignees: Vereinigte Osterreichische Eisenund Stahlwerke-Alpine Montan Aktiengesellschaft, Vienna, Austria; Establissement Wanderfield & C0., Schaan, Liechtenstein [22] Filed: Sept. 7, 1973' [21] Appl. No: 395,293

[301 Foreign Application Priority Data Primary Examiner-Henry S, Jaudon Attorney, Agent, or Firm-Kurt Kelman 57 ABSTRACT A flat weaving machine is operable to form a shed terminating at a fell of a cloth, to enter a filling thread into said shed along a predetermined line, to cut off said filling thread, and to beat up said filling thread against said fell. The machine comprises an intermittently rotatable reed roller consisting of a reed shaft and a multiplicity of discs co-rotationally mounted on said reed shaft and formed with thread-engaging edge portions which are adapted thus to beat up successive filling threads against said fell as said reed roller is intermittently rotated in a predetermined direction. Tensioning means are provided for maintaining the tension of said filling thread as it is beaten up and comprise two stationary spring tongues, which are disposed at opposite ends of said reed roller and bear on the outer end faces of those said discs which are disposed at said opposite ends of said reed roller. Said tongues are adapted to clamp opposite end portions of said filling thread against said outer end faces when said filling thread has been cut off. Said tensioning means also comprise two thread tensioners disposed adjacent to opposite ends of said reed roller and comprising backing means disposed adjacent to said predetermined line. Said tensioners are pneumatically operable to force said filling thread against said backing means when, and only when, said filling thread has thus been entered into said shed.

9 Claims, 3 Drawing Figures FllLLllNG THREAD TENSIONING MEANS This invention relates to an apparatus for maintaining the tension of a filling thread when it has been entered into the shed and has thereafter been cut off and is being beaten up in fiat weaving machines comprising an intermittently rotating reed roller which consists of a multiplicity of thin discs aligned on a common shaft and having thread-engaging edge portions for beating up the filling thread against the fell of the cloth, in which apparatus a clamp for clamping the end of the filling thread cooperates with the outer end face of at least one of the end discs of the reed roller.

A problem arising in fiat weaving machines which comprise an intermittently rotating reed roller resides in that the filling thread is to be entered into the shed without obstruction and, when the filling thread has been entered, the laterally protruding end portions of the filling thread are to be retained so that these end portions of the filling thread cannot be pulled into the shed and the filling thread is not too loose adjacent to the selvage. To enable the weaving of a fabric which is uniform throughout its width, the tension of the filling thread as it is beaten up should be uniform throughout the width of the cloth.

In a known weaving machine comprising a pivotally oscillatable sley (Swiss Patent Specification No. 424,667), suction nozzles for retaining the filling thread are used to avoid a rebounding of filling thread and an occurrence of loose filling thread portions in the woven fabric. These nozzles are disposed on both sides of the shed and are pivoted on an axis which is parallel to the direction of the filling thread so they can retain the filling thread even as it is beaten up by the sley. This arrangement has the disadvantage that it involves ahigh structural expenditure and that the filling thread may becomeloose in a certain portion as it is beaten up by the sley because, before it is beaten up, the filling thread extends diagonally from the fell to the sley at the other end of the shed and is held in this position and the filling thread is beaten up against the fell to extend parallel thereto so that the excess length which is due to the previous diagonal position results in a reduction of the tension of the filling thread. Besides, the filling thread is not cut off after each shot but is shot back into the shed so that there are no free ends of the filling thread adjacent to the selvage.

In another known weaving machine (Austrian Patent Specification No. 184,876) the shed is formed by means of a drum and a rotatably mounted rubber wheel is forced against one end of said drum so that the rubber wheel rotates in unison with the drum. The filling threads are entered by means of needles and clamped in position between the rubber wheel and the drum so that the needles can be retracted from the shed without taking the filling thread along. Because the rubber wheel rotates in unison with the drum, a relative movement by which the filling thread would be tensioned cannot take place between the rubber wheel and the end face of the drum. The filling thread is retained with the slight tension under which it is transferred, and a uniform tension of the filling thread throughout the width of the cloth cannot be obtained.

It is an object of the invention to eliminate these disadvantages and to provide an apparatus which is of the kind described first hereinbefore and which is relatively simple in construction and maintains the filling thread,

and particularly its end portions, taut until the filling thread has been tied in.

This object is accomplished according to the invention in that a stationary spring tongue forming the clamp engages each of the two end discs of the reed roller, which end disc may be thicker than the remaining discs, and that stationary thread tensioners respectively precede and succeed the reed roller inthe direction of the shot in the area in which the filling thread is entered and pneumatically force the filling thread against backing means only after the filling thread has been entered. As the filling thread is entered, it is lifted from the backing means associated with the thread tensioner and is drawn into the shed without obstruction. When the filling thread has been entered, the filling thread is pneumatically forced against the backing means because the filling thread is no longer subjected to the tension exerted by the shuttle so that the thread is braked against a displacement as a result of the friction between the thread and the backing means. As the filling thread is beaten up, the thread is pulled away from the pneumatic thread tensioner and would lose its tension adjacent to the selvage unless each of the spring tongue bearing against the end discs of the reed roller retains the thread between said spring tongue and the end disc. Whereas the filling thread is taken along by the reed roller during the rotation thereof, the filling thread is simultaneously braked by the stationary spring tongue so that the required tension of the filling thread is ensured.

According to the invention the backing means with which each thread tensioner cooperates consist of two beads which extend transversely to the direction of the filling thread and which may be provided with a friction facing, if desired, and the inlet opening of a vacuum conduit is disposed in known manner between said beads. An outlet opening of a pressure conduit is suitably in register with and spaced from the inlet opening of the vacuum conduit. Compared to known arrangements comprising vacuum conduits or thread-guiding tubes into which the thread is blown by a pressure conduit having an outlet opening which opens adjacent to the inlet opening, this arrangement has the advantage that a directed air stream is produced which ensures that the end portions of the filling threads will be forced against the backing means. The pressure difference between the pressure and vacuum conduits is selected so that the moving filling thread does not contact the friction facing of the backing means as the filling thread is entered but is held in a hovering condition at that time. As soon as the filling thread has been arrested, the pressure difference is sufficient to force the end portions of the filling thread against the backing means so as to maintain the tension under which the filling thread has been entered. The filling thread is yieldably held because the end portions of the filling thread may be pulled under tension as the filling thread is beaten up. This could hardly be achieved with a mechanical holder. Because the mouths of the two conduits of the thread tensioners are spaced apart, the entering of the filling thread is not obstructed.

According to a preferred embodiment of the invention, the spring tongues are provided adjacent to the orbital path of the thread-engaging edge portions of the end discs with an edge portion which extends approximately radially to the reed shaft and serves to deflect the end portions of the filling thread so that the end portions of the filling thread are reliably pulled into the clamping nip and cannot slip over the spring tongues.

Projections extending in the direction of rotation are provided at the outer ends of the thread-engaging edge portions of the end discs and ensure that the end portions of the filling thread are actually taken along by the thread-engaging edge portions during the rotation of the reed and do not slip off from the thread-engaging edge portions in a radially outward direction. This is mainly important because the end portions of the filling thread are retained by the spring tongues.

To increase the clamping action between the spring tongues and the end discs of the reed roller, these end discs are provided with friction facings on their outer end faces.

Finally, the initial stress of the spring tongues, i.e., the spring force with which the tongues bear on the outer end faces of the end discs, can be varied to enable an adaptation to the thickness and structure of the filling thread.

An embodiment of the invention is shown diagrammatically and by way of example in the accompanying drawing, in which FIG. I is a transverse sectional view taken through the reed roller of an apparatus according to the inventron,

FIG. 2 is a top plan view showing the apparatus with the pressure tube omitted, and

FIG. 3 is a partly sectional view taken in the direction of the filling thread through the vacuum tube.

The reed roller comprises an intermittently rotating shaft 1, on which a multiplicity of axially aligned, thin discs 2 are co-rotationally mounted. The end discs 3 are thicker than the remaining discs 2. All reed roller discs 2, 3 have thread-engaging edge portions 4 by which the filling thread 5 which has been entered is beated up against the fell of the cloth during the rotation of the reed shaft. In the area in which the filling I thread is entered, two thread tensioners are associated with the reed roller and respectively precede and succeed the same in the direction of the filling thread. Each thread tensioner consists of a lower vacuum tube 6 provided with an inlet opening 7 and a pressure tube conduit 8 which has an outlet opening which is spaced from the inlet opening 7. The edges of the opening of the vacuum conduit 6 extend transversely to the direction of the filling thread and consist of beadlike backing means 9, which are provided with a friction facing, preferably consisting of synthetic resin and having a roughened or knurled surface.

Spring tongues 10 bear on the outer end faces of the end discs 3 and are secured to the machine frame 11 by means of slots so that the contact pressure between the tongues and the end faces of the discs can be varied. The end discs 3 are provided at their ends with friction facings, not shown. Adjacent to the orbital path of the thread-engaging edge portions 4 of the discs 3 of the reed roller, each spring tongue 10 has a deflecting edge 12 which is approximately radial to the reed shaft I and around which the filling thread 5 is trained when the reed shaft rotates in the direction indicated by the arrow as the filling thread is beaten up. A a result, the filling thread is pulled into the clamping nips between the spring tongues 10 and end discs 3. To prevent during this rotation a slipping of the filling thread 5 from the thread-engaging edge portions in a radially outward direction, the thread-engaging edge portions are provided with porjections 13 extending in the direction of rotation.

Filling thread 5 is entered by a shuttle (not shown) which moves in a guideway constituted in the illustrated embodiment by machine frame 11 along reed shaft 1. After the filling thread has been entered in the shed, it is cut and pressed against the friction facings of beadlike backing means 9. In this manner, the filling thread is maintained in the illustrated tensioned condition. Intermittent rotation of the reed shaft by an angle determined by the distance between two adjacent edge portions 4 causes the filling thread to be beaten up while the filling thread is taken along by the threadengaging edge portion and projection 13, and the two ends of the cut filling thread are pulled off the friction facings of backings 9 and into the nips between spring tongues 10 and end discs 3.

After the filling thread has been beaten up and a new filling thread has been entered, the reed shaft is rotated by the next angular increment and the operation is repeated. When the filling thread is entered or inserted into the shed, the tension exerted upon the thread by the shuttle suffices to guide the filling thread between vacuum tube 6 and pressure tube 8 without the thread contacting either tube. As soon as the filling thread comes to rest, however, no tension is exerted thereon and the air stream between tubes 5 and 8 presses filling thread 5 against the friction facings of backings 9, thus braking the thread in the direction of the extension of the filling thread. As clearly shown in FIG. 3, the filling thread extends across inlet opening 7 of vacuum tube 6 when it is pressed against the friction facings.

What is claimed is:

1. In a fiat weaving machine which is operable to form a shed terminating at a fell of a cloth, to enter a filling thread into said shed along a predetermined line, to cut off said filling thread, and to beat up said filling thread against said fell, said machine comprising an intermittently rotatable reed roller consisting of a reed shaft and a multiplicity of discs co-rotationally mounted on said reed shaft and formed with threadengaging edge portions which are adpated thus to beat up successive filling threads against said fell as said reed roller is intermittently rotated in a predetermined direction, the provision of tensioning means for maintaining the tension of said filling thread as it is beaten up, said tensioning means comprising two stationary spring tongues, which are disposed at opposite ends of said reed roller and bear on the outer end faces of those of said discs which are disposed at said opposite ends of said reed roller, said tongues being adapted to clamp opposite end portions of said filling thread against said outer end faces when said filling thread has been cut off, and

two thread tensioners disposed adjacent to opposite 3. Tensioning means as set forth in claim 1, in which said backing means of each of said tensioners comprise two beads extending transversely to said predetermined line and each of said tensioners comprises a vacuum conduit having an inlet opening disposed between said beads.

4. Tensioning means as set forth in claim 3, in which said beads are provided with a friction facing.

5. Tensioning means as set forth in claim 3, in which each of said tensioners comprises a pressure conduit having an outlet opening which is in register with and spaced from said inlet opening.

6. Tensioning means as set forth in claim 1, in a weaving machine in which the thread-engaging edge portions of each of said discs at said opposite ends of said roller are adapted to revolve so as to describe an orbital path, in which tensioning means each of said spring tongues is provided with an edge portion which extends.

comprise friction facings provided on said outer end face of said discs at the opposite ends of said'reed roller.

9. Tensioning means as set forth in claim 1, in which said spring tongues are under a variable initial stress. 

1. In a flat weaving machine which is operable to form a shed terminating at a fell of a cloth, to enter a filling thread into said shed along a predetermined line, to cut off said filling thread, and to beat up said filling thread against said fell, said machine comprising an intermittently rotatable reed roller consisting of a reed shaft and a multiplicity of discs corotationally mounted on said reed shaft and formed with threadengaging edge portions which are adpated thus to beat up successive filling threads against said fell as said reed roller is intermittently rotated in a predetermined direction, the provision of tensioning means for maintaining the tension of said filling thread as it is beaten up, said tensioning means comprising two stationary spring tongues, which are disposed at opposite ends of said reed roller and bear on the outer end faces of those of said discs which are disposed at said opposite ends of said reed roller, said tongues being adapted to clamp opposite end portions of said filling thread against said outer end faces when said filling thread has been cut off, and two thread tensioners disposed adjacent to opposite ends of said reed roller and comprising backing means disposed adjacent to said predetermined line, said tensioners being pneumatically operable to force said filling thread against said backing means when, and only when, said filling thread has thus been entered into said shed.
 2. Tensioning means as set forth in claim 1, in which said discs at said opposite ends of said reed roller are thicker than others of said discs.
 3. Tensioning means as set forth in claim 1, in which said backing means of Each of said tensioners comprise two beads extending transversely to said predetermined line and each of said tensioners comprises a vacuum conduit having an inlet opening disposed between said beads.
 4. Tensioning means as set forth in claim 3, in which said beads are provided with a friction facing.
 5. Tensioning means as set forth in claim 3, in which each of said tensioners comprises a pressure conduit having an outlet opening which is in register with and spaced from said inlet opening.
 6. Tensioning means as set forth in claim 1, in a weaving machine in which the thread-engaging edge portions of each of said discs at said opposite ends of said roller are adapted to revolve so as to describe an orbital path, in which tensioning means each of said spring tongues is provided with an edge portion which extends approximately radially to said reed shaft and adjacent to said orbital path and is engageable by and adapted to deflect one end portion of said filling thread.
 7. Tensioning means as set forth in claim 1, which comprise projections formed on the outer ends of said thread-engaging edge portions of said discs at the opposite ends of said reed roller, said projections extending in said predetermined direction.
 8. Tensioning means as set forth in claim 1, which comprise friction facings provided on said outer end face of said discs at the opposite ends of said reed roller.
 9. Tensioning means as set forth in claim 1, in which said spring tongues are under a variable initial stress. 